Maria Balouktsi

Net-zero buildings: incorporating embodied impacts

The design and assessment of net-zero buildings commonly focus exclusively on the operational phase, ignoring the embodied environmental impacts over the building life cycle. An analysis is presented on the consequences of integrating embodied impacts into the assessment of the environmental advantageousness of net-zero concepts. Fundamental issues needing consideration in the design process – based on the evaluation of primary energy use and related greenhouse gas emissions – are examined by comparing three net-zero building design and assessment cases: (1) no embodied impacts included, net balance limited to the operation stage only; (2) embodied impacts included but evaluated separately from the operation stage; and (3) embodied impacts included with the operation stage in a life cycle approach. A review of recent developments in research, standardization activities and design practice and the presentation of a case study of a residential building in Norway highlight the critical importance of performance indicator definitions and system boundaries. A practical checklist is presented to guide the process of incorporating embodied impacts across the building life cycle phases in net-zero design. Its implications are considered on overall environmental impact assessment of buildings. Research and development challenges, as well as recommendations for designers and other stakeholders, are identified.

Erratum to: Cumulative energy demand in LCA: the energy harvested approach

Correction Due to a misinterpretation of an information source, the characterisation factor of geothermal energy within the approach ‘CED energy statistics approach’ was wrongly reported and applied. This affected the case study results using this approach. In this paper, the correct tables and figures are displayed. The characterisation factor of geothermal energy in the approach ‘CED energy statistics’ is 1.0, and not 7.0 (see Table 3). The cumulative energy demand, renewable of the residential building Rautistrasse according to the ‘CED energy statistics’ approach, is 76 MJ wood-eq./ma, and the total cumulative energy demand is 421 MJ oil-eq./ ma (see Table 6). Over the whole life cycle of the building, the use phase causes 70 % of the cumulative energy demand according to the approach ‘CED energy statistics’ (Table 7), followed by the manufacturing and construction phase (17 %), the replacement (11 %) and the end of life stage (1 %).

From Energy Demand Calculation to Life Cycle Environmental Performance Assessment for Buildings: Status and Trends

This paper provides an overview of topics and trends that have shaped the current approaches to environmental performance assessment of buildings as part of an overall sustainability assessment. Until recently, most of the focus on reducing energy demands in buildings has been to manage and reduce their operational energy consumption through better design and management in use. However, as building codes become stricter and more buildings are constructed to higher energy standards, energy consumed during the life cycle stages other than the operation grows in relative importance to the overall energy impact. In response, recent trends involve (1) the increasing acknowledgement of the need to shift toward a life cycle approach to the quantification of building energy consumption and (2) the broadening of the assessment scope beyond primary energy demand to include a wider range of environmental (and health-related) issues. The discussion in this paper is built around these two prevailing trends.